W3School TIY Editor

#include <stdio.h> #include <math.h> int main() { printf("%f\n", log2(64.0)); printf("%f\n", log2(10.0)); printf("%f\n", log2(3.1623)); printf("%f\n", log2(1.0)); printf("%f\n", log2(0.0)); printf("%f\n", log2(-1.0)); return 0; }